Systems and methods for monitoring a parameter of a subterranean formation using swellable materials

ABSTRACT

A system for monitoring a parameter of a subterranean formation using swellable materials is disclosed. The system may include a sensor device configured to detect a parameter of a subterranean formation. The system may also include a swellable material configured to position the sensor device toward a surface of the subterranean formation by swelling of the swellable material. The system may further include a telescoping section coupled to the sensor device and emplaced in the swellable material. The telescoping section may be configured to extend with the positioning of the sensor device.

BACKGROUND

The present invention relates to monitoring subterranean formations andmore particularly, systems and methods for monitoring a parameter of asubterranean formation using swellable materials.

Monitoring of reservoir behavior due to injection and productionprocesses is an important element in optimizing the performance andeconomics of completion and production operations. Examples of theseprocesses may include hydraulic fracturing, water flooding, steamflooding, miscible flooding, wellbore workover operations, remedialtreatments and many other hydrocarbon production activities, as well asdrill cutting injection, CO₂ sequestration, produced water disposal, andvarious activities associated with hazardous waste injection. Becausethe changes in the reservoir may be difficult to resolve with surfacemonitoring technology, it may be desirable to emplace sensor instrumentsdownhole at or near the reservoir depth in either special monitor wellsor within the injection and production wells.

Challenges with downhole measurements may include securely couplingsensor packages to the rock mass, isolating the packages as much aspossible from noise in the wellbore, and providing cabling paths (ifnecessary) for transmitting data to the surface. Sensors may be deployedpermanently or retrievably. Retrievable sensors packages are oftendeployed on wirelines, but also on coiled tubing or production tubing.Wireline deployed arrays may use clamp arms, magnets, or bow springs forcoupling to the wellbore, whereas coiled tubing or tubing deployedarrays may have decentralizers and may be locked into the wellborethrough friction and bending stresses. However, these types ofdeployment may be susceptible to coupling problems if the clamp arms donot fully extend, if magnets are placed over scale or other wellboreirregularities, or if the coiled tubing is not wedged against the casingwall.

Permanent sensors may be cemented in place, but this can be a difficultand costly process for sizable sensor arrays. Successful deployments oflarge sensor arrays may have inserted the sensors coupled to tubinginside cemented casing with the tubing then cemented inside the casing.Attempts to directly place sensor arrays on the outside of casing haveoften been unsuccessful due to damage to the array during emplacement. Asuccessful deployment of cemented sensors may remain susceptible tonoise transferred either up or down the tubulars because of theaffixation to the tubing or casing.

FIGURES

Some specific exemplary embodiments of the disclosure may be understoodby referring, in part, to the following description and the accompanyingdrawings.

FIGS. 1A and 1B are partial schematic cross-sectional views of amonitoring system using swellable materials in accordance with anexemplary embodiment of the present invention.

FIG. 2 is schematic perspective view of a monitoring system usingswellable materials in accordance with an exemplary embodiment of thepresent invention.

FIG. 3 is schematic perspective view of a monitoring system usingswellable materials in accordance with an exemplary embodiment of thepresent invention.

FIGS. 4A, 4B, 4C and 4D are schematic cross-sectional views of amonitoring system using swellable materials in accordance with anexemplary embodiment of the present invention.

FIGS. 5A, 5B, 5C, 5D, 5E, 5F, 5G, 5H, 5I and 5J are schematic partialcross-sectional views of a monitoring system using swellable materialsin accordance with an exemplary embodiment of the present invention.

While embodiments of this disclosure have been depicted and describedand are defined by reference to exemplary embodiments of the disclosure,such references do not imply a limitation on the disclosure, and no suchlimitation is to be inferred. The subject matter disclosed is capable ofconsiderable modification, alteration, and equivalents in form andfunction, as will occur to those skilled in the pertinent art and havingthe benefit of this disclosure. The depicted and described embodimentsof this disclosure are examples only, and not exhaustive of the scope ofthe disclosure.

SUMMARY

The present invention relates monitoring subterranean formations andmore particularly, systems and methods for monitoring a parameter of asubterranean formation using swellable materials.

In one aspect, a system for monitoring a parameter of a subterraneanformation using swellable materials is disclosed. The system may includea sensor device configured to detect a parameter of a subterraneanformation. The system may also include a swellable material configuredto position the sensor device toward a surface of the subterraneanformation by swelling of the swellable material. The system may furtherinclude a telescoping section coupled to the sensor device and emplacedin the swellable material. The telescoping section may be configured toextend with the positioning of the sensor device.

In another aspect, a system for monitoring a parameter of a subterraneanformation using swellable materials is disclosed. The system may includea sensing tool configured to detect a parameter of a subterraneanformation. The sensing tool may include a generally tubular body. Thesystem may also include a swellable material on an exterior surface ofthe generally tubular body. The swellable material may be configured toanchor the sensing tool in a position corresponding to a surface of thesubterranean formation by swelling of the swellable material.

In yet another aspect, a method for monitoring a parameter of asubterranean formation is disclosed. The method may include introducinga sensing tool to a wellbore. The sensing tool may include a generallytubular body and is configured to detect a parameter of a subterraneanformation. The method may also include positioning the sensing tool in aposition corresponding to a surface of the wellbore by swelling aswellable material. The swellable material may be disposed on anexterior surface of the generally tubular body. The method may alsoinclude detecting a parameter of a subterranean formation with thesensing device.

Certain embodiments of the present disclosed provide for a retractablesensor device and/or tool that may reenter a retracted state. Certainembodiments provide for swell controls that may be adapted for swellingand/or de-swelling swellable materials.

The features and advantages of the present invention will be apparent tothose skilled in the art. While numerous changes may be made by thoseskilled in the art, such changes are within the spirit of the invention.

DETAILED DESCRIPTION

The present invention relates monitoring subterranean formations andmore particularly, systems and methods for monitoring a parameter of asubterranean formation using swellable materials.

The systems, apparatuses and methods of the present disclosure may allowfor the deployment of sensors in permanent, semi-permanent, and/orretrievable applications with minimal effect on the wellbore, superiorcoupling to the rock mass, minimal vibrational degrees of freedom, andsignificant isolation from the wellbore noise for those cases wheremonitoring of the reservoir is desirable. In certain embodiments,sensors may be at least partially emplaced within swell packers fordirect coupling to tubulars with maximum isolation from the rock massfor cases where it is desirable to monitor the tubing deformation and/orflow noise/activity within the tubing. Such swell packers may beconstructed of elastomers that swell when exposed to either hydrocarbonsor water, depending upon the application, in order to seal off andisolate zones within the wellbore. The swell packers may providecoupling by swelling and forcing a sensor package against either aformation, a wellbore, or any rigid contact point. In certainembodiments, swellable materials may be implemented to centralize ordecentralize sensors and/or sensor tools within a wellbore, depending onthe desirability of placing the sensors and/or sensor tools in a centralor decentralized position.

Illustrative embodiments of the present invention are described indetail herein. In the interest of clarity, not all features of an actualimplementation may be described in this specification. It will of coursebe appreciated that in the development of any such actual embodiment,numerous implementation-specific decisions must be made to achieve thespecific implementation goals, which will vary from one implementationto another. Moreover, it will be appreciated that such a developmenteffort might be complex and time-consuming, but would nevertheless be aroutine undertaking for those of ordinary skill in the art having thebenefit of the present disclosure.

To facilitate a better understanding of the present invention, thefollowing examples of certain embodiments are given. In no way shouldthe following examples be read to limit, or define, the scope of theinvention. Embodiments of the present disclosure may be applicable tohorizontal, vertical, deviated, or otherwise nonlinear wellbores in anytype of subterranean formation. Embodiments may be applicable toinjection wells as well as production wells, including hydrocarbonwells. In addition well bore and well casing implementations,embodiments may be applicable for securely planting surface instrumentsin soft, crumbly ground.

FIG. 1A illustrates a system 100 where a tubular body 105 having an axis105A is shown disposed in a wellbore 140 and adjacent to the wall 120.As depicted, the tubular body 105 may be disposed in an uncased sectionof wellbore 140, but the tubular body 105 may be disposed in a casedsection or in near-surface ground in other embodiments. The tubular body105 may provide a conduit for formation fluids to travel therethrough.The system 100 may include a sensor package 110 fully or partiallyencased in a swellable element 115. The sensor package 110 may bedisposed at or near an outer boundary of the swellable element 115.

It should be clearly understood that the principles of this disclosureare not limited to use with a particular sensor, sensor package, sensingdevice or tool. Instead, the principles of this disclosure areapplicable to wide variety of devices, tools and methods. Two commonsensors for reservoir monitoring are seismic and deformation sensors.The sensor package 110 may include, for example, a sonde, a geophone, anaccelerometer, a hydrophone, or another device that detects groundmotion due to either source shots (e.g., vertical seismic profiling orcrosswell surveys) or passive behavior such as microseismicity and/ornoise in both the wellbore and the reservoir. Also, for example, thesensor package 110 may include a sensor for measuring deformation in thedownhole environment, such as a tiltmeter that measures the gradient ofdisplacement, or any instrument that measures differential displacementin the reservoir.

A line 135 may be coupled to the sensor package 110. The line 135 may beany one, or a combination, of a multi-conductor cable, a singleconductor cable, a fiber optic cable, a fiber optic bundle, and aconduit or umbilical that contains cables, fiber optics and controllines to provide a hydraulic connection down hole. In certainembodiments, the line 135 may be a wireline. In certain embodiments, theline 135 may be a means of placing the sensor package 110 in thewellbore 140. In the alternative, the sensor package 110 and theswellable material may be coupled to the tubular body 105 and introducedinto the wellbore 140 together. The line 135 may also be a means ofcommunicating electrical signals, such as indications of a parameterassociated with the subterranean formation, between the sensor package110 and a data collection system and/or control system at remotelocation, such as the earth's surface or a subsea location. In certainembodiments, the line 135 may be a means of communicating with anotherwell tool at another location in the wellbore 140 or another wellbore.As depicted, a portion of the line 135 may be encased in the swellableelement 115. In alternative embodiments, the sensor package 110 maycommunicate via any type of telemetry, such as acoustic, pressure pulse,electromagnetic telemetry or any wireless means.

Referring next to FIG. 1B, therein is depicted the system 100 of FIG. 1Awith the swellable element 115 in an expanded configuration. When theswellable element 115 comes in contact with an activating agent, theswellable element 115 expands radially outwardly. As illustrated in FIG.1B, the swellable element 115 may come in contact with the wellbore wall120 due to swelling. The sensor package 110 may include a telescopingsection 130 configured to extend outwardly toward the wall 120 alongwith the expansion of the swellable element 115 such that the swellableelement 115 in effect pulls the sensor package 110 toward the wall 120.In certain embodiments, the swellable element 115 may force the sensorpackage 110 to come into contact with the wall 120 and/or to partiallyor completely protrude into the wall 120. The telescoping section 130may include any means by which the sensor package 110 may be displacedwhile maintaining connection with the portion of the line 135 encased inthe swellable element 115. For example, the telescoping member 130 mayinclude an extensible arm or an expandable cavity within the swellableelement 115 that houses a length of the line 135 with sufficient slackcorresponding to the displacement of the sensor package 110.

Certain embodiments may employ a single swellable element 115 asdepicted in FIGS. 1A and 1B. Other embodiments may employ multipleswellable elements. Though not shown in FIGS. 1A and 1B, one or moreadditional swellable elements may be placed about the tubing 105.

It is recognized that the swellable element 115 may be made of differentmaterials, shapes, and sizes. For example, the swellable element 115 maybe deployed on tubing with a symmetrical ring configuration. Theswellable element 115 may take an annular form surrounding or partiallysurrounding the tubing 105, and may be any elastomeric sleeve, ring, orband suitable for expanding within a space between tubing 105 and anouter tubing, casing, or wellbore.

The term “swell” and similar terms (such as “swellable”) are used hereinto indicate an increase in volume of a material. Typically, thisincrease in volume is due to incorporation of molecular components of afluid into the swellable material itself, but other swelling mechanismsor techniques may be used, if desired. The swellable element 115 mayinclude one or more swellable materials that swell when contacted by anactivating agent, such as an inorganic or organic fluid. In oneembodiment, a swellable material may be a material that swells uponcontact with and/or absorption of a hydrocarbon, such as oil. In anotherembodiment, a swellable material may be a material that swells uponcontact with and/or absorption of an aqueous fluid. The hydrocarbon isabsorbed into the swellable material such that the volume of theswellable material increases creating a radial expansion of theswellable material when positioned around a base pipe which creates aradially outward directed force that may operate to radially extendtelescoping members as described above. The swellable material mayexpand until its outer surface contacts the formation face in an openhole completion or the casing wall in a cased wellbore. The swellablematerial accordingly may provide the force to extend the telescopingmember 130 of the sensor package 110 to the surface of the formationsuch as wellbore wall 120.

Suitable swellable elements include, but are not limited, to theswellable packers disclosed in U.S. Pat. Nos. 3,385,367; 7,059,415; and7,143,832; the entire disclosures of which are incorporated byreference. In certain embodiments, the swellable element 115 may beindividually designed for the conditions anticipated for a particularcase, taking into account the expected temperatures and pressures forexample. Some exemplary swellable materials may include elasticpolymers, such as EPDM rubber, styrene butadiene, natural rubber,ethylene propylene monomer rubber, ethylene-propylene-copolymer rubber,ethylene propylene diene monomer rubber, ethylene-propylene-dieneterpolymer rubber, ethylene vinyl acetate rubber, hydrogenizedacrylonitrile butadiene rubber, acrylonitrile butadiene rubber, isoprenerubber, butyl rubber, halogenated butyl rubber, brominated butyl rubber,chlorinated butyl rubber, chlorinated polyethylene, chloroprene rubberand polynorborene.

As discussed above, these and other swellable materials may swell incontact with and by absorption of hydrocarbons so that the swellablematerial expands. In one embodiment, the rubber of the swellablematerials may also have other materials dissolved in or in mechanicalmixture therewith, such as fibers of cellulose. Additional options maybe rubber in mechanical mixture with polyvinyl chloride, methylmethacrylate, acrylonitrile, ethylacetate or other polymers that expandin contact with oil. Other swellable materials that behave in a similarfashion with respect to hydrocarbon fluids or aqueous fluids also may besuitable. Those of ordinary skill in the art, with the benefit of thisdisclosure, will be able to select an appropriate swellable material foruse in the present invention based on a variety of factors, includingthe desired swelling characteristics of the swellable material and theenvironmental conditions in which it is to be deployed.

In some embodiments, the swellable materials may be permeable to certainfluids but prevent particulate movement therethrough due to the porositywithin the swellable materials. For example, the swellable material mayhave a pore size that is sufficiently small to prevent the passage ofthe sand therethrough but sufficiently large to allow hydrocarbon fluidproduction therethrough. For example, the swellable material may have apore size of less than 1 mm.

As discussed above, the activating fluid/agent may comprise ahydrocarbon fluid or an aqueous fluid. In addition, an activating fluidmay comprise additional additives such as weighting agents, acids,acid-generating compounds, and the like, or any other additive that doesnot adversely affect the activating fluid or swellable material withwhich it may come into contact. For instance, it may be desirable toinclude an acid and/or an acid-generating compound to at least partiallydegrade any filter cake that may be present within a wellbore. One ofordinary skill in the art, with the benefit of this disclosure, willrecognize that the compatibility of any given additive should be testedto ensure that it does not adversely affect the performance of theactivating fluid or the swellable material.

The activation agent may be introduced to the swellable material in avariety of ways. The activation agent may be injected into the wellboreor casing from a source at the surface. In other embodiments, theactivation agent may be placed in the wellbore or casing and released ondemand. In yet other embodiments, swelling of the swellable material maybe delayed, if desired. For example, a membrane or coating may be on anyor all surfaces of the material to thereby delay swelling of thematerial. The membrane or coating could have a slower rate of swelling,or a slower rate of diffusion of fluid through the membrane or coating,in order to delay swelling of the material. The membrane or coatingcould have reduced permeability or could break down in response toexposure to certain amounts of time and/or certain temperatures.Suitable techniques and arrangements for delaying swelling of aswellable material are described in U.S. Pat. Nos. 7,143,832 and7,562,704, the entire disclosures of which are incorporated herein byreference.

The swellable materials of certain embodiments may be shrinkable or maybe distintegratable. A deactivating fluid/agent, for example, maycomprise a salt compound that would cause the swelled materials tocontract by way of osmosis. A disintegrating fluid/agent, for example,may comprise any chemical adapted to chemically destroy the swellablematerial. In either case, the shrinking or disintegrating of theswellable material allows for the unanchoring of the sensor device ortool.

In alternative embodiments, the system 100 may comprise a samplingpackage (not shown) in lieu of or in addition to the sensor package 110.The sampling package may comprise an extendable straw or functionalequivalent. When the swellable element 115 comes in contact with anactivating agent, the swellable element 115 expands radially outwardlyand may seal about an area of the wellbore wall 120. The samplingpackage, coming into contact with the formation, may facilitate fluidflowing from the formation such that the fluid may be monitored by thesensors. Alternatively or additionally, the fluid from the formation atthat spot may be used as a fluid power source. Alternatively oradditionally, the sampling package, coming into contact with theformation, may obtain a sample from the location. Then, by way of thede-swelling processes disclosed herein, the system 100 may be retractedfrom the wellbore 120 and the sample may be recovered from the samplingpackage.

FIG. 2 illustrates a system 200 where a swellable element 215 providesfor symmetric instrument tool clamping within a borehole or casing. Atool 205 may be or include a sensor device, a microseismic array tool,or any other tool for which vibrations degrade its fidelity. Asdepicted, the tool 205 may comprise a tubular body and may be disposedin an uncased section of the wellbore 240. Alternatively, the tool 205may be disposed in a cased wellbore. Certain embodiments may includeumbilical lines, wirelines, or tubes to the surface that could beincorporated to provide for positioning and/or monitoring the tool 205and downhole sensors, for electrically activated controls of subsurfaceequipment, for injecting chemicals, or any combination thereof. Inalternative embodiments, communication with the tool 205 may be achievedvia any type of telemetry, such as acoustic, pressure pulse orelectromagnetic telemetry.

One or more swellable elements 215 may be coupled to the tool 205 andmay be configured to expand to anchor symmetrically, or substantiallysymmetrically, the tool 205 against a wall 220 of the wellbore orcasing. For example, the swellable elements 215 may be configured toswell, due to contact with an activation agent, to a position 210. Asillustrated by the position 210, the swellable elements 215 may come incontact with the wall 220 upon expansion.

The swellable elements 215 may be any elastomeric sleeve, band, ring, orother annular form surrounding or partially surrounding the tubing 205and suitable for expanding between the tool 205 and wall 220, as long asthe swellable elements 215 anchor the tool 205 in a symmetrical orsubstantially symmetrical manner. For example, when a configuration ofthe swellable elements 215 fully ring the tool 205, the tool 205 maybecome well-centered in the wellbore or casing so that microseismicenergy may reach the tool 205 substantially equally well from all sides.In certain embodiments, a symmetric, or substantially symmetric, systemsimilar to system 200 may surround a geophone planted in a shallowsurface borehole to suppress decoupled oscillations of the instrument.

The areal contact of the swellable elements 215 with the tool 205provides stiffening and allows shifting of modal vibrations to higherfrequencies above the range of the microseisms or other sources that arebeing monitored. Because they expand into available space, the swellingelements themselves are very well suited for use in irregular boreholesas tool contact is necessarily hit-or-miss along the length of the toolin such settings. Similar swelling elements applied to surface-basedacquisition sensors (e.g., shallow borehole geophones or tiltmeters)allow firm emplacement that, in contrast to permanent cementation,allows subsequent retrieval and reuse. In certain embodiments, theswellable elements 215 may form seals in the wellbore 240 by swelling.The swellable elements 215 accordingly may prevent fluid from flowingoutside of an interval along the body of the tool 205. In certainembodiments, the swellable elements 215 may be configured to effectivelyisolate the entire, or nearly the entire, body of the tool 205, asdesired.

FIG. 3 illustrates a system 300 where a swellable element 315 providesfor asymmetric instrument tool clamping within a wellbore 340. One ormore swellable elements 315 may be coupled to the tool 305 in anasymmetric manner so that the swellable elements 315 anchor the tool 305in an asymmetrical manner. In such a configuration, the tool 305 may bepushed up against a side 320 of the wellbore or casing, where the tool305 may receive microseismic energy via direct contact. The swellableelements 315 may push the tool against the borehole wall more uniformlyand firmly along its length, as compared to conventional approaches.

It should be understood, in light of this disclosure, that a number ofcombinations of tubing and/or wireline run with encased, ring, orpartial ring deployment may have advantages that can be exploited for agiven monitoring situation, as for example to shield against noise,temperature, or wellbore chemistry and to appropriately couple for whatis actually being monitored.

FIGS. 4A-4D illustrate a system 400 run on wireline using an eccentricswell packer for clamping a tool 405. A swellable element 415 may runalong a length of the tool 405 to provide for asymmetric instrument toolclamping within a wellbore or casing. The swellable element 415 may fitalong a holder 410. FIGS. 4A and 4B depict the swellable element 415prior to activation. FIGS. 4C and 4D depict the swellable element 415 inan expanded position after contact with an activation agent. Theexpansion may cause the swellable element 415 and the tool 405 tocontact the wall 420 of the wellbore or casing.

FIGS. 5A-5H illustrate a system 500 where a tubular body 505 is showndisposed in a wellbore or casing 540 and adjacent to the wall 575. FIGS.5A and 5B respectively illustrate partial side and perspectives views ofthe system 500 in a retracted state. FIGS. 5C and 5D respectivelyillustrate partial side and perspectives views of the system 500 in anexpanded state. The tubular body 505 may be encircled by an innerarrangement 510 and an outer arrangement 515. The tubular body 505 maybe provided with ribbing 555 or other means configured to preventrotation of the inner arrangement 510 about the tubular body 505. Thetubular body 505 may be provided with one or more flanges 545 proximateto the inner arrangement 510 and configured to anchor the innerarrangement 510 so as to prevent axial movement with respect to thetubular body 505.

The inner arrangement 510 and the outer arrangement 515 may respectivelyinclude components 510A and 515A, disposed in a generally circular,annular and/or cylindrical arrangement. For example, as depicted in thecross-sectional representations in FIGS. 5B and 5D, one or morecomponents 510A, 515A generally form partial sectors or arcs. Thecomponents 510A, 515A may be solid or hollow pieces and may be made ofmetal, composite or another type of suitable material.

One or more sensor packages 550 may be coupled to the outer arrangement515. Each sensor package 550 may have at least a portion extending intoa component 515A. In certain embodiments, one or more sensor packagesmay be coupled to the inner arrangement 505. In certain embodiments, oneor more sensor packages may be coupled to both the inner arrangement 505and the outer arrangement 515. In the latter embodiment, the sensorpackages may be configured for noise-canceling in order to attenuatetubular-borne noise.

As depicted, the inner arrangement 510 and the outer arrangement 515 maybe coupled by way of one or more struts 520. The struts 520 may beconfigured to have a degree of freedom and, for example, may be swivablyattached to one or both of the inner arrangement 510 and the outerarrangement 515. It may be preferable that a swivel attachment beassociated with either one or the other of the inner arrangement 510 andthe outer arrangement 515, so that both may maintain a stableconfiguration during insertion into or retrieval from the borehole. Inone exemplary embodiment, the swivel attachment may be of a hinge typeand may have a vertical length around an axis of rotation. In certainembodiments, the swivel attachment may include paths for electricalsignal lines.

Adjacent components 510A, 515A may be coupled to each other. For examplewithout limitation, each component 510A, 515A may be coupled to anadjacent component 510A, 515A via a mandrel and/or an expansion sleeve.As depicted, adjacent components 510A of the inner arrangement 510 arecoupled via expansion sleeves 525. Adjacent components 515A of the outerarrangement 515 are coupled via expansion sleeves 530. The expansionsleeves 525 and 530 may partially encase, surround or otherwise wraparound portions of adjacent circular components 510A and 515A, therebyaiding the generally circular alignment of the components 510A and 515A.The expansion sleeves 525 and 530 may be made of metal, composite oranother type of suitable material.

FIGS. 5E-5J illustrate one example of an expansion sleeve 530 aboutadjacent circular components 515A. FIG. 5E illustrates an unexpandedstate, while FIG. 5F illustrates an expanded state. The adjacentcomponents 510A may be configured to allow a region 535 between themwhen not flush. Swellable elements may be disposed in the region 535. Inone example, elastomer 530A may be disposed in the region 535 with swellcontrols 560. Though not depicted, an expansion sleeve 525 and adjacentcircular components 510A may be similarly configured. The swellableelements may be configured to expand generally tangentially to the innerarrangement 510 so that the inner arrangement 510 expands generallytangentially, as opposed to radially. Thus, the swellable elements, inconjunction with other elements of system 500, provide a mechanism forthe system 500 to detach from the tubular body.

As depicted in FIG. 5G, the swell controls 560 may include fluid and/orelectrical lines 565 that may be configured to convey activation agentand/or activate valves 570. The valve 570 may include one or morereservoirs and may be operable to disperse the activation agent to theswellable materials 515A. By this or similar means, the swell controls560 may be adapted for swelling the swellable materials 515A so that thesystem 500 may detach from the tubular body.

In addition to detachment, the swellable elements may similarly providea mechanism for reattachment. For example, it may be preferable for theswellable elements to be water-swellable. A deswelling agent may includesalt to extract water from a water-swellable material by osmosis. Theelectrical lines may later be used to expose the swellable elements to adeswelling agent in order to shrink the swellable material, therebytransitioning the tool to a retracted state that would allow for toolretrieval. Thus, the swell controls 560 may be adapted for de-swellingthe swellable materials 515A.

FIGS. 5H and 5I show diagrams of one exemplary embodiment of a valve570. By way of example without limitation, the valve 570 may include adeswelling agent reservoir 572 and/or a swelling agent reservoir 574. Aslide 576 may include ports that may be selectively aligned with adeswelling agent reservoir 572 and/or a swelling agent reservoir 574.For example, FIG. 5I depicts a view of the slide where ports 578A areshown in an open state and in aligned with a reservoir port. Ports 578Bare shown in a closed state and not aligned with a reservoir port. Thevalve 570 may be configured with the slide 576 to allow for thecontrolled feed of an agent to the swellable material. The slide 576 maybe activated by hydraulics or an electrical device such as anelectromagnet on either end. In alternative embodiments, one or both ofthe valve 570 and the slide 576 may be adapted so the ports of the slidemay be selectively aligned with the ports of a reservoir by rotation,rather than lateral motion of the slide 576 indicated in FIG. 5H. Forexample, the slide 576 may have a disk form with ports that may berotated about a center.

FIG. 5J illustrates a mandrel 525A that may be used in the alternativeor in addition to expansion sleeves to couple two or more adjacentcircular components 510A and 515A. The mandrel 525A may be used as aone- or two-ended piston to prevent or minimize lateral expansion suchthat expansion is directed along an axis of the mandrel. In certainembodiments, secondary mandrels in the outer arrangement 515 may bepreferred in order to shift the centerpoint of the inner arrangement 510as the tubular body 505 may not always be well-centered in the borehole540.

Swellable elements may be included with the mandrels 525A. As depictedin FIG. 5J, a mandrel 525A may include an outer body 525B that at leastpartially surrounds an elastomer material 525C. The elastomer material525C is shown in an at least partially expanded state. The outer body525B may comprise metal, a composite, or any other suitable material.Although the mandrel 525A is depicted as having a particular shape, itshould be understood that the shape and implementation of the mandrel525A may be subject to considerable modification, as would be understoodby one of ordinary skill in the art having the benefit of thisdisclosure.

Thus, in the expanded state, the system 500 allows sensor packages to bedeployed in a state that has no direct physical contact or intermediatestructural contact with the tubular body. Having the tool placed againstthe side of the borehole with no direct solid-to-solid contact with thetubular body, the sensor packages are afforded a degree of acousticisolation from acoustics that may otherwise be transferred via thetubular body. Further, the system 500 provides a safety margin such thatthe tool may be spared from sharp, high-force, or uncontrolled movementsthat could endanger tubing, wiring, the borehole wall, or the tool. Thegenerally circular outer arrangement 515 provides a perimeter that mayallow for positioning while maintaining tolerance for irregularitiesthat may be encountered in the surface of the borehole. Although system500 is depicted with four circular components and four sensor packagesin the outer arrangement 515, and four circular components in the innerarrangement 510, it should be understood that other embodiments mayinclude a different number and combination of circular components andsensor packages.

In another embodiment, the inner arrangement 510 may be coupled tospring- powered extensions released to point inwards to the tubular body505 in order to “measure” the radial distance between the innerarrangement 510 and the tubular body 505 at three or more points. As thespring-powered extensions increasingly extend, they may restrict theflow of swelling agent into their respective components 510A, therebyallowing those swellable sections nearest the tubular to be expandedoutwards more rapidly than those farther away, and thereby centering theinner arrangement 510 at a uniform distance from the tubular body 505.Once deployed, the extensions may be refracted into the innerarrangement 510.

Certain embodiments of the present disclosure may provide a simpler,cheaper, and easier means of coupling sensors to a formation ortubing/casing that are likely to provide much surer coupling. Mostprevious sensor deployments have used cement coupling (generally forpermanent deployments), mechanical coupling such as clamp arms and bowsprings (for both permanent and retrievable applications), magneticcoupling (retrievable applications), or even uncoupled deployments(e.g., sensors attached to tubing run inside of casing) that rely onfriction and bending stresses. Methods and systems of the presentdisclosure may eliminate the need for mechanical clamp arms (which mayhave leak issues with seals and high temperature), bow springs (whichmay have poor high frequency response and resonances), magnets (whichmay have limited coupling and resonances), or cementing. Methods andsystems of the present disclosure may also improve omnidirectional arrayfidelity, even for retrievable operations and settings where theswelling elements may be subsequently de-swelled, detached or torn offto facilitate tool retrieval or repositioning.

Certain embodiments of the present disclosure may allow for long-termemplacement in difficult open-hole environments without permanentlycementing an instrument in place. This may simplify operations and mayallow for retrievable sensor devices if difficulties occur duringemplacement. This may avoid the situation in open-hole environmentswhere mechanical arms or bowsprings can sink into soft materials in thehole and cause poor tool coupling. Such a situation can occur in shalesand many shallow boreholes where sensors would otherwise have to becemented in permanently to obtain good coupling.

Certain embodiments may allow for improved signal fidelity formicroseismic monitoring of hydraulic fractures by ensuring bettercoupling compared to clamp arms, bow spring, magnets, or otheremplacement methods, thus attenuating or eliminating longitudinal toolvibrations that degrade the recording fidelity of elastic body wavemotion parallel to a tool axis. In certain embodiments, swellingelements may effectively dampen acoustic noise generated by flow inproduction tubulars as well as noise received via the tubulars. Theswelling elements may even yield sensor isolation from the tubulars eventhough swellable elements are in contact with both. Additionally,certain embodiments may allow for securely planting surface instrumentsin soft, crumbly ground.

Certain embodiments may remove directional bias of recorded signals byemplacing sensors in the center of a borehole with equal response fromall directions, as opposed to a likely higher fidelity on the side ofthe borehole on which it is deployed when clamped or cemented. Certainembodiments may eliminate the need for a nearby vertical observationwell by allowing for installation of tools in the injection/productionwell with good coupling and a degree of noise suppression from tubingactivities.

Certain embodiments may be used for time-lapse seismic monitoring and/ortime-lapse deformation monitoring throughout the life of the reservoirfor more permanent installations. The time-lapse seismic applicationrequires a source on either the surface or in a nearby well; time-lapsedeformation only requires continuous measurements of tilt or otherdeformation parameters. For emplacement of tiltmeters, geophones, orother sensors in shallow boreholes, certain embodiments provide a fast,easy method to deploy sensors, potentially allowing them to stabilizemuch faster—which translates to a shorter lead time for monitoring.

Even though the figures depict embodiments of the present disclosure ina horizontal section of a wellbore, it should be understood by thoseskilled in the art that embodiments of the present disclosure are wellsuited for use in deviated or vertical wellbores or casings.Accordingly, it should be understood by those skilled in the art thatthe use of directional terms such as above, below, upper, lower, upward,downward and the like are used in relation to the illustrativeembodiments as they are depicted in the figures, the upward directionbeing toward the top of the corresponding figure and the downwarddirection being toward the bottom of the corresponding figure.Additionally, as discussed above, embodiments of the present disclosuremay be implemented in cased or uncased wellbores, even though onlyuncased wellbores are depicted in the figures.

Therefore, the present invention is well adapted to attain the ends andadvantages mentioned as well as those that are inherent therein. Theparticular embodiments disclosed above are illustrative only, as thepresent invention may be modified and practiced in different butequivalent manners apparent to those skilled in the art having thebenefit of the teachings herein. Furthermore, no limitations areintended to the details of construction or design herein shown, otherthan as described in the claims below. It is therefore evident that theparticular illustrative embodiments disclosed above may be altered ormodified and all such variations are considered within the scope andspirit of the present invention. Also, the terms in the claims havetheir plain, ordinary meaning unless otherwise explicitly and clearlydefined by the patentee. The indefinite articles “a” or “an,” as used inthe claims, are defined herein to mean one or more than one of theelement that it introduces.

What is claimed is:
 1. A system for monitoring a parameter of asubterranean formation using swellable materials, the system comprising:a sensor device configured to detect a parameter of a subterraneanformation; a swellable material configured to position the sensor devicetoward a surface of the subterranean formation by swelling of theswellable material; and a telescoping section coupled to the sensordevice and emplaced in the swellable material, wherein the telescopingsection is configured to extend with the positioning of the sensordevice.
 2. The system of claim 1, wherein the sensor device is emplacedat least partially in the swellable material.
 3. The system of claim 1,wherein the swellable material is further configured to position thesensor device against the surface of the subterranean formation byswelling.
 4. The system of claim 1, wherein the sensor device isoperative to communicate a signal related to the parameter of thesubterranean formation.
 5. The system of claim 4, wherein thetelescoping section is configured to allow the positioning of the sensordevice while the sensor device is operative to communicate a signalrelated to the parameter of the subterranean formation.
 6. The system ofclaim 1, wherein the swellable material is on an exterior surface of atubular body and is configured to position the sensor device away fromthe pipe by swelling.
 7. The system of claim 6, wherein the swellablematerial is further configured to reduce an effect on the sensor deviceof acoustic noise traveling along the tubular body.
 8. A system formonitoring a parameter of a subterranean formation using swellablematerials, the system comprising: a sensing tool configured to detect aparameter of a subterranean formation, wherein the sensing toolcomprises a generally tubular body; and a swellable material on anexterior surface of the generally tubular body, wherein the swellablematerial is configured to anchor the sensing tool in a positioncorresponding to a surface of the subterranean formation by swelling ofthe swellable material.
 9. The system of claim 8, wherein the swellablematerial is further configured to substantially center the sensing toolbetween at least two opposing points on the surface of the subterraneanformation.
 10. The system of claim 9, wherein the swellable materialcomprises a plurality of swellable members disposed along the generallytubular body.
 11. The system of claim 9, wherein the swellable materialat least substantially surrounds a length the generally tubular body.12. The system of claim 8, wherein the swellable material is configuredto anchor the sensing tool against the surface of the subterraneanformation.
 13. The system of claim 12, the swellable material comprisesa plurality of swellable members disposed along the generally tubularbody, wherein each swellable member partially surrounds a correspondinglength of the generally tubular body.
 14. The system of claim 12,wherein the swellable material longitudinally extends along a length ofthe generally tubular body.
 15. A method for monitoring a parameter of asubterranean formation, the method comprising: introducing a sensingtool to a wellbore, wherein the sensing tool comprises a generallytubular body and is configured to detect a parameter of a subterraneanformation; positioning the sensing tool in a position corresponding to asurface of the wellbore by swelling a swellable material, wherein theswellable material is disposed on an exterior surface of the generallytubular body; and detecting a parameter of a subterranean formation withthe sensing device.
 16. The method of claim 15, wherein the positioningstep comprises substantially centering the sensing tool between at leasttwo opposing points on the surface of the wellbore.
 17. The method ofclaim 16, wherein the swellable material comprises a plurality ofswellable members disposed along the generally tubular body.
 18. Themethod of claim 16, wherein the swellable material at leastsubstantially surrounds a length the generally tubular body.
 19. Themethod of claim 15, wherein the positioning step comprises anchoring thesensing tool against the surface of the wellbore.
 20. The method ofclaim 19, wherein the swellable material longitudinally extends along alength of the generally tubular body.